So yeah, there is such a game and it should've been released today, June 6 (probably PST), on Steam. However, because of an online petition and obviously due to its blatant controversial nature, it did not push through. I think there's discussions everywhere about the ban of the game and it's basically become a free speech vs censorship kinda thing.

I'm gonna try to look for it. Someone probably uploaded it to a torrent site or something.

"Marketing materials for the game say players will be able to choose between portraying a SWAT team member responding to a shooting or portraying an actual shooter whose objective is to 'hunt and destroy.'"

Apparently it's just one person that made the game; some Russian troll who has been banned before on Steam while under a different name. He marketed the game as a 'police tactical response' game and that's why it got as far as it did, passing all that red tape and managing to get to the public release phase. The guy's known for abusing customers and publishing copyrighted material, so it seems.